I just got the same false rejection on a model I just uploaded. The issue might not be 100% corrected yet.

On a separate note: Is there some reason shapeways' automated system no longer includes a reason for the rejection and just says there was a problem? I remember they used to include the error messages (invalid input, empty output, incorrect size, etc.) that, while sometimes cryptic, used to help you figure out why the upload was rejected by the system. It seems like for the last few months all the emails say is there was a problem but give no feedback.